按照功能区分，电梯由电力拖动、曳引、_、轿厢、_、门、电器控制、安全保护等8个功能系统。
参考答案：导向,对重平衡
We ______ such great success without your efforts. Thanks a lot.
A．shouldn’t have accomplished
B．couldn’t have accomplished
C．were unable to accomplished
D．mustn’t have accomplished
一患者突发心动过速，心电图如图所示，下列哪项不符合该心电图诊断的临床表现()
A．症状突然发作，突然好转
B．心尖区第一心音强度一致
C．心率160～200次/分，心律规则
D．大多有器质性心脏病
E．诱发呕吐后发作突然终止
